1. Field of the Invention
The invention relates to a device for hand-driven operation of a guided wheel.
2. Description of the Related Art
A multiplicity of hand-driven devices are known from the prior art, which, particularly in the case of bicycles, ensure, in addition to the known foot-pedal drive, an additional hand-operated auxiliary drive of one of the wheels.
DE 101 06 283 A1 discloses a device for hand-driven operation of a guided wheel which is arranged on a steering gear and which is pivotable about a steering axis oriented perpendicularly with respect to the axis of rotation of the guided wheel.
This device comprises a first handle with a first coupling means arranged on the first handle and a second handle with a second coupling means arranged on the second handle. The first and the second coupling means are coupled via coupling points, so as to transmit tractive force, to a force transmission train for transmitting a movement of the handles to a drive means cooperating with the hub of the guided wheel. The drive means converts the movement of the handles into a rotational movement of the guided wheel with the aid of the force transmission train.
Furthermore, a guide means is provided, which is pivotable about the steering axis and cooperates mechanically with the steering gear. The guide means ensures, furthermore, that the handles are mounted movably. For this purpose, the guide means has a mechanical positive guide such that the handles can be moved symmetrically with respect to a steering plane of symmetry in which the steering axis lies and which is oriented perpendicularly to the axis of rotation of the guided wheel.
The coupling means of the device known from DE 101 06 283 A1 are designed as two chain wheels spaced axially apart from one another. These have drive levers arranged radially on the gearwheels and having the handles. On each of the two sides of the hub of the guided wheel, a toothed drive pinion having a freewheel is arranged, the force transmission train in the form of a link chain being guided between the toothed drive pinions and the chain wheels of the coupling means. In order to provide a handy step-up of the drive device, it is necessary to design the diameter of the chain wheels of the coupling means so as to be markedly larger than the diameter of the toothed drive pinions. To actuate the drive, it is necessary to set the chain wheels of the coupling means in an alternating rotational movement by means of the radial drive levers. On account of the abovementioned size ratios of the diameters, the result of this is that the moved parts of the hand-operated drive have comparatively high moments of inertia and the device as a whole possesses an appreciable weight.